Smart antenna technology is directed to antennas having the ability to change radio beam transmission and reception patterns to suit the environment within which radio communication systems operate. Smart antennas have the advantage of providing relatively high radio link gain without adding excessive cost or system complexity.
Smart antenna technology has been used in wireless communication systems for decades, and has recently been investigated for use in wireless local area networks (WLANs). In a WLAN, a client station (CS) is a device used by a mobile end user for communication with other stations within the same WLAN or with other entities outside of the WLAN. Central hubs that provide distribution services in WLANs are referred to as access points (APs). Access points are similar to base stations in wireless telecommunication systems.
A client station can be equipped with a smart antenna as well as an antenna steering algorithm that enables the antenna to switch electronically to a particular directional antenna beam. This enables the client station to communicate with its access point while achieving high performance.
Example client stations are personal computers operating with a wireless network card, such as a PCMCIA (personal computer memory card international association) card, for example. The wireless network card may be compatible with the 802.11 standard, for example, and may include a smart antenna where a number of directional antenna beams are defined as well as an omni-directional antenna beam. The antenna gain of each directional antenna beam is greater than the antenna gain of the omni-directional antenna beam, resulting in an increased range in which a client station can access the network via the access point.
The PCMCIA card requires a driver, which resides in the client station. On one end, the driver provides commands to and/or receives raw data from the PCMCIA card. On the other end, the driver interfaces with an antenna steering algorithm, which, in certain circumstances, resides in the application layer in the client station.
The raw data received by the driver includes information that is to be passed through an application program interface (API) to the antenna steering algorithm in the application layer. As an example, the raw data may include signal-to-noise (S/N) ratios and received signal strength indicators (RSSI) for the signals received by the different directional antenna beams. This data, which may be referred to as object identifiers (OIDs), is then passed to the antenna steering algorithm.
For the antenna steering algorithm to receive the OIDs, customized addresses are assigned at the driver by the PCMCIA card manufacturer. Because of this address customization, translation errors may occur. An example translation error is when the S/N ratios and RSSI values received by the driver are provided to the antenna steering algorithm in a certain order, but the algorithm reads the raw data in a different order. Consequently, the antenna steering algorithm needs to be debugged so that the translation error can be corrected. This is a time consuming and costly approach to correct.